Cardinal Hermite interpolation using positive definite functions

In this paper, we study cardinal Hermite interpolation by using positive definite functions. Among other things, we establish a procedure that employs the multiquadrics for cardinal Hermite interpolation.     

A Diversity Model Based on Dimension Entropy and Its Application to Swarm Intelligence Algorithm

The swarm intelligence algorithm has become an important method to solve optimization problems because of its excellent self-organization, self-adaptation, and self-learning characteristics. However, when a traditional swarm intelligence algorithm faces high and complex multi-peak problems, population diversity is quickly lost, which leads to the premature convergence of the algorithm. In order to solve this problem, dimension entropy is proposed as a measure of population diversity, and a diversity control mechanism is proposed to guide the updating of the swarm intelligence algorithm. It maintains the diversity of the algorithm in the early stage and ensures the convergence of the algorithm in the later stage. Experimental results show that the performance of the improved algorithm is better than that of the original algorithm.     

A flame‐retardant DOPO‐MgAl‐LDH was prepared and applied in poly (methyl methacrylate) resin

A novel inorganic and organic composite flame retardant (9,10‐dihydro‐9‐oxa‐10‐phosphaphenanthrene‐10‐oxide [DOPO]–layered double hydroxide [LDH]) was synthesized via grafting DOPO with organic‐modified Mg/Al‐LDH, which was introduced into poly (methyl methacrylate) (PMMA) resin to prepare the flame‐retardant PMMA composites. Thermogravimetric analyzer (TGA) showed that the T_‐50% of DOPO‐LDH/PMMA composites enhanced by about 20°C, and with the 20% flame retardant, the residual char content can be increased by 39.8% in the air atmosphere compared with LDH/PMMA composites. In the UL‐94 and the limiting oxygen index (LOI) tests, it can be found that compared with LDH/PMMA composites, the LOI value of DOPO‐LDH/PMMA composites were raised evidently with the increased flame retardants, and the droplet combustion was greatly improved. These results could be ascribed to the action of DOPO free‐radical, catalytic charring of polymer and the effect of LDH physical barrier. Moreover, the novel DOPO‐LDH not only given PMMA a good flame‐retardant property and thermal stability, but also have higher visible light transmittance, ultraviolet‐shielding effect, and low loss of mechanical properties, which could further facilitate the wide application of inorganic environment‐friendly flame retardants in general resins and engineering resins and broaden the application of polymers.     

Direct and Inverse Sobolev Error Estimates for Scattered Data Interpolation via Spherical Basis Functions

The purpose of this paper is to get error estimates for spherical basis function (SBF) interpolation and approximation for target functions in Sobolev spaces less smooth than the SBFs, and to show that the rates achieved are, in a sense, best possible. In addition, we establish a Bernstein-type theorem, where the smallest separation between data sites plays the role of a Nyquist frequency. We then use these Berstein-type estimates to derive inverse estimates for interpolation via SBFs.     

核酸适配体生物传感器在三聚氰胺检测中的应用进展

三聚氰胺常被非法添加到食品中,以提高食品中蛋白质的含量。但是,三聚氰胺一旦进入体内,会对人们的健康造成伤害。因此,对三聚氰胺的检测十分必要。为了弥补传统仪器检测法和免疫检测法的不足,基于核酸适配体开发了一系列新的生物传感器,用于三聚氰胺的检测。按照与三聚氰胺的不同识别机制,把这些新的生物传感器分成了四类,分别为基于多聚胸腺嘧啶DNA链和三聚氰胺识别的生物传感器、基于无嘌呤位点的三链DNA结构和三聚氰胺识别的生物传感器、基于核酸适配体和三聚氰胺识别的生物传感器、基于三聚氰胺和汞离子/铜离子等配位识别的生物传感器。本文按照上述四类方法逐个展开,对核酸适配体生物传感器在三聚氰胺检测中的应用进行了综述,并对它们的优缺点进行阐述。     

基于三角晶格光子晶体谐振腔的双通道解波分复用器

提出了一种基于三角晶格二维光子晶体解波分复用器。该器件主体由线缺陷波导、环形谐振腔及点缺陷微腔构成。使用平面波展开法研究了线缺陷波导的特性,给出了线缺陷波导的能带图,对局部器件微调后进行大量的性能仿真以及对整体器件进行性能仿真,选择合适的器件参数,并使用时域有限差分法研究了不同波长的光在解波分复用器中的传输特性,并给出了电场分布图。仿真结果表明,该种结构可以实现波长分别为1271nm和1291nm两种光波的解波分复用。采用6个额外的介质柱,提高了环形腔的透射率;并通过在入射波导的入射口处增加三对介质柱,提高了波导的出射效率,从而整体上提高了双通道解波分复用器的输出效率。     

三乙酸铊氧化3.5—环—24—S—乙基—胆甾—22—烯—6—酮反应的研究

油菜甾醇内酯(Brassinolide,1)是一种高效的植物生长促进剂,其活性与侧链C_22,C_23邻二羟基的构型密切相关,当C_(22),C_(23)为S,S构型时,其活性仅为1的10％左右,在油菜甾醇内酯(1)及其同类物的合成中,C_(22),C_(23)邻二羟基的引入多采用OsO_4氧化法,但所得的主要产物却是非期望的C_(22)S,C_(23)S-二羟基化合物。     

Synthesis of uniform anatase TiO2 nanoparticles by gel-sol method. 3. Formation process and size control

Uniform anatase-type TiO(2) nanoparticles were prepared by the gel-sol process from a condensed Ti(OH)(4) gel preformed by the hydrolysis of a Ti-triethanolamine (TEOA) complex. The particle size of the anatase TiO(2) was increased from ca. 5 to 30 nm with pH increasing from 0.6 to 12 by aging the Ti(OH)(4) gel at 140 degrees C for 72 h, while the yield of the anatase TiO(2), 100% below pH 9.6, started to decrease from pH 10, to 67% at pH 11.5 and only 9% at pH 12.2. These results reveal a significant reduction of the nucleation rate of the anatase TiO(2) with increasing pH, as is explained by the reduction of the concentration of a precursor complex, Ti(OH)(3)(+), and the adsorption of hydroxide ion onto the embryos of TiO(2). Triethanolamine appeared to enhance the pH effect on the nucleation rate of anatase TiO(2) particles by adsorption onto their embryos, leading to the wide range of the size control. Triethanolamine was also found to act as a shape controller of the anatase TiO(2) particles for yielding ellipsoidal particles from Ti(OH)(4) gel at a relatively high pH above 11. The particle size was also controlled by seeding of anatase TiO(2). Moreover, the seeding experiment suggested that the rate-determining step of the gel-sol process was not the dissolution of the hydroxide gel, but the deposition of the monomeric precursor from the solution phase.     

液晶润滑的研究进展*

综述了近10多年来国内外液晶润滑及液晶添加剂的研究进展。概括了溶致液晶和热致液晶的润滑性能的理论研究及实验结果, 比较了不同类型液晶的润滑机理及在不同实验条件下的抗减摩性能, 以及它们作为普通润滑剂、合成油脂等的添加剂时的润滑效果。